JPH022331Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field This invention is applied in connection with the casting of teeth using wax patterns in dentistry, and is applicable to dental prostheses, especially crowns, bridges, or inlays. This invention relates to a sprue bar structure for easily removing a wax pattern such as the above from a working model without deformation, eliminating deformation during burial, and producing a highly accurate casting.

(B) Prior Art Conventionally, in the production of wax patterns in dentistry, wax is still frequently used for sprue implantation of crowns, bridges, inlays, etc. This sprue planting technique using wax has the problem that the wax has a low strength against heat or physical external forces, so it deforms during the planting and pouring processes, making it impossible to form accurate castings. Was. Therefore, in recent years, it has been proposed to use a plastic prover instead of wax in producing the wax pattern. However, the conventional plastic provers 1', 1''
Since the runner part 2' and the sprue bar part 3' are integrally molded as shown in FIGS. 9A and 9B, for example, in the part shown in FIG. 9A, the runner part 2' is aligned with the tooth row. Although it was possible to bend and deform the sprue, since the distance between the sprue bars and the direction thereof were constant, the freedom of sprue planting was compromised. On the other hand, in the case shown in FIG. 9B, the spacing between the tips of the sprue bar section 3'' can be adjusted by tilting it, but there is a limit to this adjustment, and the bending deformation of the runner section 2'' This has the problem of reducing the flexibility of bending deformation of the runner section. As described above, the sprue bar used for sprue planting in the conventional wax pattern technique cannot be freely adjusted and deformed to suit various tooth rows, so it is difficult to adjust the flow of metal during casting. It has disadvantages such as non-uniformity and lack of mold stability.

(c) Problems to be solved by the invention This invention is capable of arbitrarily bending and deforming the teeth and adjusting the spacing between each tooth or the teeth in order to suit the needs of various dentitions. It is an object of the present invention to provide a sprue bar assembly in which the distance and angle between the sprue bars formed corresponding to each tooth can be adjusted according to the upright angle of the sprue bar assembly.

(d) Means for solving the problem In order to achieve the above-mentioned purpose, this invention specifically uses a circular cross-section made of thermoplastic material that can be plastically deformed along the tooth row. It is constituted by a combination of a runner bar member and a sprue bar element also made of thermoplastic material, and the sprue bar element is slidable in the axial direction of the runner bar member and rotated around the axis of the runner bar member. A plastic sprue bar assembly for casting comprising a connecting base movably resiliently engaged to the runner bar member, and a sprue bar leg extending on the opposite side of the connecting base. .

(e) Description of Embodiments The plastic prover assembly for casting according to this invention will be described in detail below based on specific embodiments shown in the drawings.

The plastic sprue bar assembly 1 for casting according to this invention is composed of a runner bar member 2 and a sprue bar element 3. The runner bar member 2 and the sprue bar element 3
Both are molded from thermoplastic materials such as polymethyl methacrylate.
The runner bar member 2 can be bent and deformed along the teeth by heating during use, and is made of, for example, a round bar with a circular cross section and a diameter of about 3 mm. On the other hand, the sprue bar element 3 is elastic with respect to the runner bar member 2 so as to be slidable in the axial direction of the runner bar member 2 and rotatable around the axis of the runner bar member 2. a connecting base 4 that is attached to the
The sprue bar leg 5 extends on the opposite side of the connection base 4. The connecting base 4 has a pair of opposing clamping pieces 6, 6, and the clamping pieces 6,
Each opposing surface of 6 cooperates with the runner bar member 2.
a clamping surface 7 with an inner diameter suitable for surface contact with the outer peripheral surface of the
form 7. The tips of the clamping pieces 6, 6 are smaller than the diameter of the runner bar member 2, and are opened at a distance suitable for elastically passing through the outer diameter of the runner bar member 2. hand,
After the runner bar member 2 has passed, the sprue bar element 3 is resiliently attached to the runner bar member 2 so as to be slidable in the axial direction thereof and rotatable around the axis. It's summery. On the other hand, the sprue bar leg portion 5 of the sprue bar element 3 includes a conical portion 8 tapering from the connecting base 3 toward the opposite side thereof, and a straight rod portion 9 extending outward from the tip of the conical portion 8. It has The conical portion 8 acts as an effective casting channel when the sprue bar assembly 1 is incinerated, and the straight rod portion 9 is formed into an appropriate length when planting the wax pattern WP. The length of the sprue bar element can be adjusted by cutting the sprue bar element.

The plastic prover assembly 1 for casting having the above structure is used in the following manner. First, the sprue bar element 3 is attached to the runner bar member 2 according to the dentition T of the impressed wax pattern WP.
are attached to form the sprue bar assembly 1.
The runner bar member 2 is deformed into a toothed and correspondingly curved shape, as shown in FIG. The runner bar member 2 is easily plastically deformed by heating and maintains its shape after cooling. On the other hand, as shown in FIGS. 5A and 5B, the sprue bar elements 3 are arranged such that the distance between them is adjusted according to the tooth row, and the angle is adjusted according to the inclination of the tooth row as shown in FIG. Set. The sprue bar assembly 1 assembled in this way is planted in the wax pattern WP on the working model, as shown in Fig. 7, and buried in the truncated cone of the flask F (see Fig. 8). .
Sprue bar assembly 1 embedded in this way
is completely incinerated together with the wax pattern in connection with the flow waxing process of the wax pattern, and forms a highly accurate casting mold without being deformed during the process.

(f) Effects of the invention As described above, the plastic prover assembly for casting according to this invention has teeth and a runner bar member that can be plastically deformed accordingly, and the distance between the teeth and the inclination of the teeth. It is composed of a combination of sprue bar elements whose mutual distance and mutual angle can be adjusted, and can be suitably applied to any type of tooth. Furthermore, the sprue bar assembly is made of strong material, prevents deformation during work processes such as burial, maintains a constant flow of metal during casting, has excellent mold stability, and does not leave any gas after being incinerated. Another advantage is that it can be completely incinerated together with the pattern.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the runner bar member according to this invention, FIGS. 2A, B, and C are plan, front, and side views of the sprue bar element, and FIG. 3 is a perspective view showing the assembled state. Figure 4 is a plan view showing a modified form of the runner bar member in an application example of a long stern bridge, and Figures 5A and 5B are
6 is a side view showing how to adjust the spacing of the sprue bar elements according to the spacing between the teeth, FIG. 6 is a side view showing how the angle of the sprue bar elements is adjusted depending on the inclination of the teeth, and FIG. FIG. 8 is a side sectional view showing the manner in which the wax pattern is planted, FIG. 8 is a side sectional view showing the manner in which the wax pattern is buried in the flask, and FIGS. 9A and 9B are side views showing a conventional example. DESCRIPTION OF SYMBOLS 1... Sprue bar assembly, 2... Runner bar member, 3... Sprue bar element, 4... Connection base, 5... Sprue bar leg, 6, 6... Holding piece, 7, 7... Holding surface, 8 ...Conical part, 9
... Straight rod-shaped part, WP ... Wax pattern, T
...dentition.

Claims (1)

[Claims for Utility Model Registration] (1) Consisting of a runner bar member made of a thermoplastic plastic material and having a circular cross section that can be plastically deformed along the tooth row, and a sprue bar element also made of a thermoplastic plastic material. and the sprue bar element is resiliently engaged with the runner bar member so as to be slidable in the axial direction of the runner bar member and rotatable about the axis of the runner bar member. 1. A plastic spruver assembly for casting, comprising a connecting base and a spruver leg extending on the opposite side of the connecting base. (2) The sprue bar leg portion of the sprue bar element is comprised of a conical portion that tapers from the connecting base toward the opposite side thereof, and a straight rod portion that extends outward from the tip of the conical portion. A plastic prover assembly for casting according to claim (1) of the utility model registration, characterized in that: (3) The plastic sprue bar assembly for casting according to claim (1), wherein the runner bar member and the sprue bar element are made of polymethyl methacrylate.